The overall goal of the Immunology & Virology Core is to provide a centralized resource for detailed analysis of cellular and humoral immune responses for all investigators in this HIVRAD project. The Immunology & Virology Core will assist in the planning of assays, carry out assays of cellular and humoral immune responses for animals from multiple different projects, thus allowing accurate comparisons of immune responses among different experimental groups, serve as central repository for common reagents and experimental protocols, and assist in the interpretation and presentation of immunologic data. Specific assays that will be provided by the Immunology & Virology Core include standard and polychromatic flow cytometric analysis; analysis of cell-mediated immune responses using MHC tetramers, ELISPOT and intracellular cytokine staining; analysis of humoral immune responses using ELISA assays, Western blot and SIV neutralization assays; MHC class I typing by PCR; and preparation of virus stocks for challenge and neutralization assays.